Math Problem Statement

Using a ruler and a protractor, make an accurate drawing of the triangle shown below. Measure length b in your drawing. Give your answer to 1 d.p.

Solution

To solve this triangle problem, let's determine the length bb, which represents the hypotenuse of the triangle. The given triangle includes the following details:

  1. The triangle has:
    • One angle of 3030^\circ,
    • One adjacent side of 8cm8 \, \text{cm},
    • One opposite side of 7cm7 \, \text{cm}.

We will use trigonometric relationships to calculate the hypotenuse bb.


Step-by-Step Solution

Step 1: Use the cosine rule

The hypotenuse bb can be found using the formula for cosine: cos(θ)=adjacenthypotenuse\cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} Substituting θ=30\theta = 30^\circ and adjacent side 88: cos(30)=8b\cos(30^\circ) = \frac{8}{b}

Step 2: Solve for bb

b=8cos(30)b = \frac{8}{\cos(30^\circ)}

We know cos(30)=320.866\cos(30^\circ) = \frac{\sqrt{3}}{2} \approx 0.866, so: b=80.8669.2cmb = \frac{8}{0.866} \approx 9.2 \, \text{cm}

Thus, the length of bb is approximately 9.2 cm (to 1 decimal place).


Final Answer:

b=9.2cm\boxed{b = 9.2 \, \text{cm}}

Would you like me to explain how to verify this or expand on another part of the solution?


Relative Questions:

  1. How do you determine the hypotenuse if you know two sides instead of an angle?
  2. What is the significance of the cosine rule in solving non-right triangles?
  3. How do you calculate the sine of 3030^\circ, and when would you use it here?
  4. How can the Pythagorean theorem assist in solving similar triangle problems?
  5. What other methods can be used to construct such a triangle with precision?

Tip:

Always ensure your calculator is set to degrees (not radians) when solving trigonometric problems involving angles in degrees!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Triangle Properties

Formulas

cos(θ) = adjacent / hypotenuse

Theorems

Cosine Rule

Suitable Grade Level

Grades 9-11